python如何实现自定义异常类

class SometypeErroe(Exception):

def __init__(self,errorInfo):

Exception.__init__(self)

self.errorInfo=errorInfo

def __str__(self):

return str(self.errorInfo)+'你想说的内容'

a=int(input('输入'))

if 10<a<50:

print(a)

else:

raise SometypeErroe(a)